s = input()
l = s.split()
Z = ['zero', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine']
RZ = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
PR = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997]
if s.count(' ')==2:
    if (l[0] in Z) and (l[1] in Z) and (l[2] in Z) and (l[0] != 'zero'):
        C1 = Z.index(l[0])
        C2 = Z.index(l[1])
        C3 = Z.index(l[2])
        C1R = RZ[C1]
        C2R = RZ[C2]
        C3R = RZ[C3]
        Z = C1R*100 + C2R*10 + C3R
        def closest(PR, Z):
            return PR[min(range(len(PR)), key = lambda i: abs(PR[i] - Z))]
        print(closest(PR, Z))
    else:
        print("Wrong input")
else:
    print("Wrong input")
